Motion capture has numerous applications. For example, in filmmaking, digital models generated using motion capture can be used as the basis for the motion of computer-generated characters or objects. In sports, motion capture can be used by coaches to study an athlete's movements and guide the athlete toward improved body mechanics. In video games or virtual reality applications, motion capture facilitates interaction with a virtual environment in a natural way, e.g., by waving to a character, pointing at an object, or performing an action such as swinging a golf club or baseball bat. The term “motion capture” refers generally to processes that capture movement of a subject in three-dimensional (3D) space and translate that movement into, for example, a digital model or other representation.
Motion-capture systems may utilize one or more cameras to capture sequential images of an object in motion, and computers to analyze the images to reconstruct an object's shape, position, and orientation as a function of time. For 3D motion capture, at least two cameras are typically used. In order to accurately track motion in real or near-real time, the camera(s) of motion-capture systems typically operate at a frame rate of at least 15 image frames per second.
Unfortunately, however, image acquisition at such high rates entails significant power requirements, which can be exacerbated by the need for adequate lighting to facilitate image capture. Power requirements can pose a practical limit to the range of applications of motion-capture systems, as excessive power consumption can render their employment impractical or economically infeasible.
What is really needed are techniques that leverage the mechanical impact of a touch to facilitate low-power operational modes unavailable with purely optical systems. For example, a touch may “wake up” a device from a low-power standby mode using an electrical signal from a piezo or electromagnetic actuator.